Can anyone remember the name of a practical joke that Oor Wullie and his pals used to play on people ? It involved a whole length of thread or string, a metal washer or button or similar near to one end of the thread and a drawing pin. You pin one end (with the washer near) to a window head or sash, get out of sight and pull the other end again and again so the dangling washer keeps hitting the window and annoying the people inside.